The present invention relates to infusion devices for subcutaneous delivery of a medication or a therapeutic fluid by means of an external infusion system and more particularly to an infusion device having releasably connected means for delivery of the medication or the therapeutic fluid from the external infusion system.
Infusion devices are generally known in the art for delivering a medication or a therapeutic fluid to a subcutaneous site in a patient by means of a cannula inserted through the patients skin to the subcutaneous site. Such devices commonly comprise a tubular cannula extending from a housing adapted to receive the desired medication via disconnectable means for suitable connection to further components of the infusion system. The possibility of disconnecting the infusion device from the further parts of the infusion system is provided in order to improve the user comfort. The user is enabled to perform activities which do not allow the presence of a pump or the like, or which are hindered by the presence of a pump or the like. In the disconnected state only a part of the infusion device is worn by the patient. This allows for increased mobility. In order to provide such disconnectable means and still maintain a fluid-tight sealing towards the interior of the housing and the tubular cannula that prevents contamination of the infusion site, such devices are commonly provided with a self-sealing penetrable septum on either the housing or the disconnectable part and a hollow needle on the other part adapted to penetrate the septum. Upon withdrawal of the needle from the septum this provides a fluid-tight sealing towards the interior of the housing. The septum and the needle further provides a fluid-tight sealing between the housing and the connector means when medication or therapeutic fluid is delivered to the patient from the external infusion system. Upon connection of the connector in relation to the housing the needle is inserted through the septum. In order to facilitate the placement and to ensure the correct penetration site for the a needle guide means is provided on either the housing or the connector. Further locking means are provided in order to secure the position of the connector in relation to the housing. Subcutaneous infusion devices of this generally known type are disclosed in e.g. U.S. Pat. No. 5,522,803 to Teissen-Simony and U.S. Pat. No. 5,545,143 to Fischell.
The manufacture of such a device is connected with problems since small dimensions are required in order to satisfy the user need for an mainly not visible device. Although the presently known infusion devices to some extent provide a help during the connection of the connector in relation to the housing, the assembling of the housing and the connector is due to these small dimensions still connected with great difficulty especially for patients with reduced sight or physical handicaps.
For these reasons there is a need for improvements in the infusion devices of the type mentioned in the foregoing, and particularly with respect to providing an infusion device which is far less cumbersome from a manufacturing point of view and which provides for a simplified connecting process while maintaining the desired small dimensions of such an infusion device. The infusion device according to the invention remedies the above mentioned disadvantages and provides further advantages which will become apparent from the following description.